Collecting and Analyzing Data on Greenhouse Gases

Scientists have been collecting data about changes in atmospheric concentrations of greenhouse gases. Observations of conditions over the 1st century indicate that we are heading for conditions never before seen by modern man.
 
Scientists get information about the past atmospheric gas concentrations from a variety of sources. Ice cores provide evidence for variation in greenhouse gas concentrations over the past 800,000 years.
 
Both carbon dioxide and methane vary between glacial and interglacial phases, and concentrations of these gases correlate strongly with temperature.